The higher esters of substituted cinnamic acids, particularly the octyl methoxy cinnamates, are well known sunscreen agents which possess high absorption in the 300-400 nm range and which are ideally suited for cosmetic applications since they are non-irritating to the skin and provide lubricity to prevent drying effects of wind and sun. However, a major consideration in the use of such cinnamates is economic. The high production costs associated with substantial product losses during the current stripping and washing stages coupled with the generation of highly acidic wastes which must be neutralized before disposal in order to satisfy environmental regulations, is mainly responsible for the cost of the cinnamate products. Other important factors contributing to product cost are a relatively low product yield, the formation of undesirable phenyl ester, dimer and polymer cinnamate by-products during the slow rate of transesterification in current processes and the use of environmentally objectionable aromatic solvents and their decomposition products which require dilution before release to the atmosphere.
Accordingly, it is an object of this invention to provide a process for the manufacture of alkoxy cinnamate esters which eliminates or minimizes the volume of material requiring neutralization or dilution of harmful effluents generated in the system.
Another object of the invention is to provide a commercially feasible process which reduces the cost of alkoxy cinnamate manufacture by at least 10 per cent.
Still another object of the invention is to provide an integrated, continuous process for the production of alkoxy cinnamate sunscreen agents.
Yet another object is to provide a process for the conversion of lower alkoxybenzaldehyde to a higher alkyl alkoxy cinnamate which significantly eliminates or minimizes acidic waste and venting of toxic vapors.
Another object is to provide a self-sustaining process, ideally suited for continuous operation, which greatly reduces the volume of waste and treatment thereof.
These and other objects of the invention will become apparent from the following description and disclosure.